Method and apparatus for retting flax and other fibers.



N. T. BACON.

METHOD AND APPARATUS FOR BETTING FLAX AND OTHER FIBERS. APPLICATION FILED APR. 26. 1917.

Patented Mar. 5, 1918.

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UNITED STATES PATENT 0mm.

NATHANIEL T. BACON, OF PEACE DALE, RHODE ISLAND.

I METHOD AND APPARATUS FOR, BETTING FLAX AND OTHER FIBERS.

Specification of Letters Patent.

Patented Mar. 5, 1918.

Application filed April 26. 1917. Serial No. 64,629.

To all whom it may concern:

Be it known that I, NATHANIEL T. BACON,

a citizen of the United States, residing at Peace Dale, R. 1., have inventedcertain new and useful Improvements in Methods and Apparatus for Retting- Flax and other Fibers, of which the following is a clear, full, and exact description.

My invention relates to the retting of flax or other fibers, and it has for its object to produce a better grade of fiber and to simplify the control of the retting process.

- The retting of flax and other fibers is accomplished principally by two processes, first, by exposure to dew, and second, by steeping in Water; in either case the end sought is accomplished by means of fermentative or putrefactive processes. As is well-known, these processes are much accelerated by the use of appropriate temperatures, the best average temperature being generally in the neighborhood of 32 0. My experiments go to show that somewhat different temperatures are advisable for different kinds of fibers, and that better re sults are obtained by using different temperatures at different stages of the operation I have also found that different parts of'the same plant require somewhat different treatment, as the root, the main stem and the top do not all ret at the same rate under the same conditions, and that consequently it is advisable to compensate the differences by different temperatures for different parts of the same plant.

In order to obtain the best results, it is occasionally necessary to completely check the operation as can readily'be accomplished by raising thetemperature at any stage to a point where the bacteria produced in the operation are all killed, and then beginning fermentation over again with fresh bacteria.

The final purification can be accelerated by washing the flax with heated fresh water, which is subsequently used in retting successive charges. In this manner the volume of water.requisite for retting is materially reduced, which is of considerable importance where this water has to be purified in order to obtain good results and is economical of heat in all cases. Moreover, as the retting process, under the condition's'which I emdrawal from theflax of the retting water of highbacterial content and the substitution therefor of fresh water of low bacterial content furnishes means for controlling the retting process near the end of the operation and therefore reduces the danger of overretting. A uniform product is thus easily obtained.

One form of apparatus adapted for the practice of my new. method comprises a group of retting units such as tanks or compartments, which are so connected together that a continuous flow of retting liquor may be maintained through any number of consecutive units arranged in a retting series.

In the drawings wherein I have illustrated such an apparatus in a more or less diagrammatic and schematic way,

Figure 1 is a view .of a number of the units and associated parts employedin my process;

Fig. 2 is a plan shown in Fig. 1;

Fig. .3 is a vertical section of a unit showing a modified form of heat controlling view of one of the units means; and

Fig. 4 is a plan diagram of a complete batte of units, the connecting and other pipes not being shown in detail.

While I have shown the tanks which constitute the units of my apparatus as arranged in a row, this is not essential, and I may arrange them according to any grouping which circumstances require Each of the tanks has side walls 2 and a bottom wall 3, and is provided with an opening 4 at the bottom of one side and an opening 6 at the top of the opposite side. In the opening 4 is fitted a pipe 8 provided with a handoperated valve 10; the upper opening 6 is g provided with a pipe 12 having a hand-operated valve 14. The pipes 8 and 12 are connected by a'vertical pipe 16 which, extending upward, connects with a fresh water main 18, and, extending downward; connects .at its other end with the waste main 20; this pipe 16 has between its junction with the as to dimensions, etc., as the relative position of the tanks may require, it being untank of each series through the pipes 8 and 16 by opening the valves 10 and 22 therein, the adjacent valves 14 and 24 being closed. The Water rises in the tank and overflows into the pipe 12 on the opposite side of the tank; the valve 14 therein being open as is also the valve 10 for the succeeding tank, while the valves 22 and 24 in the pipe 16 between the two tanks are closed.. The flow continues thus through all the tanks in the particular series. The water overflowing through the pipe-12 of the last tank in the series into the adjacent pipe 16 is permitted to discharge into the waste main '20 by opening the valve 24 in said pipe 16, the adja" cent valve 8 having been closed.

If flow in the opposite direction is desired, the fresh water is introduced at the top of the tank that is to be the first of the series, through the pipes 16 and 12, as may be readily understood. In such case, of course, the series will run from right to left instead of from left to right as in the previous case.

Each tank may be provided with a perforated plate or screen 25 supported a short distance above the bottom of the tank, and on the screen the roots of the flax plants rest with their stems extending upwardly. The water from the pipe 8 can therefore flow across the bottom of the tankand rise evenly through the whole area of the flax mass.

Each tank is provided with means for controlling the temperature of the water flowing therethrough, one form of such means comprising a series of horizontal pipes 26 extending around the inside'ofeach tank adj acent-the walls thereof. Each of these pipes is connected by short pipes 28 and 30 extending through the wall of the tank to vertical supply manifolds 32 and 34, which are in turn connected to mains 36 and 38. Each of the short pipes 28 and 30 is provided with, a valve 40 or 42 respectively;

At the opposie side of the tank, the horizontal pipes 26 are provided with short pipes 44 emptying into a discharge manifold48 and each fitted with an automatic check valve 46 to 'prevent return flow from the manifold. One of the mains, as 36, supplies cold water or other cooling medium, and the other main, that is 38, supplies hot water, steam or the like. It is therefore apparent that by the proper manipulation of the valves 40 and 42 to causea flow of cooling or heating fluid through a selected pipe 26, the temperature of the water at diflerent levels may be readily controlled. The manifold 48 empties into waste main 20.

In Fig. 2 I have shown a modification of.

also be introduced into the water by means of perforated pipes 50 extending across the bottom of the tank and supplied from a gas main 52. The perforated pipes are also utilized to regulate the temperature by drawing ofl water from different levels in the tanks; this is accomplished by opening the appropriate valve 47 and permitting water to discharge into the discharge manifold 48, this water being replaced by inflowing water from an adjacent tankor the fresh water main. I have found that in this manner the line of temperature demarcation at a given point can be made quite sharp, the temperature gradient due to the slow conduction of heat between the pipes and the center of the tank being avoided.

The water overflowing from one tank into the next may have its temperature changed by the introduction of a temperature regu lating medium thereinto. In the form illustrated, an extension 54 from each cold water manifold 26 opens into the adjacent pipe 12 and is provided with a valve 56, the cooled overflow water when entering the next tank tends to spread out over the bottom of the tank and establish a sharply defined zone of lowered temperature about the roots of the a flax.

, As pointed out above the retting of flax goes on at a maximum speed ata temperature of about 32 C. and it can be retarded either by raising the retting fluid above this store the water to about 32 C. as it reaches portions of the flax where retting should be accelerated. If it is found that'the main stem is being rettedtoo rapidly, it is only reaches the temperature controlling means above described, to differentiate the temperatures of the portions of the rettting water to the action of which different parts of the flax are subjected, and to independently vary these temperatures, the whole retting operation in each tank comes under control and it is,

- possible to produce a local retardation of the retting process to offset differences in the natural retting speed of the different parts of the flax so as to bring out the entire plant in uniformly retted condition, which .has not been accomplishedhitherto except accidentally.

When the system is in operation, there will be a series of tanks, each of which has beenput into operation at a later date than the preceding tank of the series, the intervals between the starting of successive tanks depending upon factors not here material. The number of tanks in series will depend on the amount of flax that the retting water can treat without becoming too foul with the products of the retting action to be effectively used. As the flax in the oldest tanks in the series is subjected to the least contaminated water, a great deal of the impurities are gradually removed in these tanks.

The freshwater entering the first tank of the series has practically no retting bacteria therein, so that it is to a considerable extent merely a wash water. In its passage through the flax in this tank, it picks up bacteria, but

even when it leaves this tank its bacterial content is low. Therefore the action in the second tank is less rapid than in the presence of retting water of a higher bacterial content, such as flows through the latertanks in the series. The retting action is therefore slowed down in the second tank.

As the flow of the water through the tanks is very slow, there will, notwithstanding the low bacterial content of the water in the first tank, be an appreciable retting action therein. This action may be lessened by heating the wash water considerably above 32 C. Thecontrol of the latter-part of the retting operation is thus facilitated and it may readily be stopped at the exact point desired. The heating of the wash water also aids in the removal by the solution of the gummy matter remaining in the flax; this heated water will ordinarily be recooled before entering the next tank, as by bubbling that is the retting, is started again with gases therethrough by means of the perforated pipes. v

When the retting action in the first tank of the series is complete, it is cut oil from the series, the next succeeding tank being made the first and a new tank being added to the discharge end of the series. The water is drained off from the cut out tank and the retted flax is removed. Fresh flax is put in and the tank is now ready to be again introduced into the series at the discharge end thereof. It will be seen, therefore, that the series of tanks in which retting is taking place progresses around the circuit of the entire group such as shown in Fig. 4:, each tank being in turn made the last of the series, that is, the last to-receive the retting water, and thereafter by degrees becoming the first of'the series. As each tank is taken out of the series, an examination of the flax therein will enable the attendant to estimate 'the stage reached by the next tank and the interval before the latter is taken out will accordingly'be lengthened or "shortened.

It may sometimes be advisable to divide a group of tanks into two or more series following each other around the circuit of the group; that is, after a tank has been cut off from the fresh water end of its series, emptied and refilled, it will be connected to the discharge end of the following series. In order to reduce the evolution of illsmelling gases, which are ordinarily given off in the later stages of the retting process and which are considered to be caused by the growth. in the retting liquor of different I kinds of bacteria than those present in the earlier and inofiensive stages of the retting, the temperature of the contents of a tank in which these later developed bacteria have obtained a foothold may be raised to approximately 95 (3., thus destroying all the bacteria andcompletely stopping the fermentation; after which the fermentation,

liquor which has been taken from some other stage of the retting operation and in which the undesirablebacteria have not appreciably developed.

While I haveabove set forth specific details of a preferred form" of my improved apparatus and method, it is to be understood that both are capable of modification within the scope of the appended claims, and

that it is not my intention that in the practice of my invention it shall be limited to the use of'the exact structure or mode of procedure herein described.

What I claim is:

1. A method of retting flax or the like, which consists in locally checking the ret-' ting action. I

2. A method of retting flax or the like, which consists in differentiating the tem V peratures of the portions of the retting medium to the action of which different parts of the flax or the like are subjected.

3. A method of retting flax or the like, which consists in independently varying the temperatures of the portions of the retting medium to the action of which difierent parts of the flax or the like are subjected.

4. A method of retting flax or the like, which consists in diflerentiating the temperatures of the portions of the retting medium to the action of which different parts of the flax or the like are subjected, and independently varying the temperatures of said different portions to cause the retting of said different parts to proceed simultaneously.

5. An apparatus for the water retting of flax and the like, comprising a tank for the retting Water and the flax, and means for causing a difference in temperature between portions of the retting water at difle'rent levels in said tank.

6. An apparatus for the water retting of flax and the like, comprising a plurality of interconnected tanks for the retting water, and independent means for controlling the temperatures of the water at different levels in each tank. g

7. A method of controlling fermentation which consists in completely stopping the fermenting action and starting the same anew.

8. A method of controlling fermentation, which consists in destroying the fermentative bacteria in the fermentative medium and adding thereto a new supply of fermentative bacteria.

, 9. A method of retting flax or the like, which consists in subjecting the flax to the influence of media which are alternately promotive of and opposed to retting action.

10. A method of retting flax or the like, which consists in subjecting the flax to the action of a retting medium, completely stopping said action, and starting said action anew.

11. A method of retting flax and the like, which consists in subjecting flax to a retting medium of high bacterial content un til the retting action is nearly complete, then subjecting the flax to'a retting medium of low bacterial content and finally washing the completely retted flax in clear water.

12. A method of retting flax or the like, which consists in treating difl'erent lots of flax with retting water of high bacterial content, withdrawing the retting water from one lot, washing said lot in fresh water, withdrawing the retting water from a sec- 'WhlCh. consists in subjecting the flax to a retting water of normal temperature until the retting action is nearly complete, and

,then subjecting the flax to water of relatively high temperature to dissolve the gummy matter remaining in the flax and to make the last part of the retting operation relatively slow.

14. An apparatus for the water retting of flax or the like, comprising a series of tanks for the retting water and the flax in which the flax remains throughout the operation, and means comprising connections between each pair oi? adjacent tanks for maintaining a constant flow of water through said tanks.

15. An apparatus for the water retting of flax or the like, comprising a group of tanks for the retting water and the flax in which the flax remains throughout the operation, and means comprising connections 7 between said tanks for maintaining a flow of water through successive tanks, said connections being arranged so as to permit the arrangement of said tanks into separate series.

16. A method of retting flax or the like in a series of tanks, which consists in subjecting the flax in one tank to a retting water of normal temperature until the retting operation is nearly complete, subjecting the flax to water of relatively high temperature to dissolve the gummy matter remaining in the flax and to make the last part of the retting operation relatively slow, and then cooling the water to the proper temperature for the succeeding tank by bubbling appropriate gases therethrough.

17. A method of regulating the water retting of flax, which consists in selectively subjecting portions of the retting water to the direct action of a gas.

18. A method of regulating the water retting of flax, which consists in selectively R.- J. HAZARD, MARY B. B. HAZARD.

Califi, this 20th 

